CN103245817B - A kind of method of measuring voltage and voltage sensor - Google Patents

Abstract

A kind of voltage sensor, emergent light order in light source is passed through first collimator, the polarizer, λ/4 wave plate, responsive optical crystal and analyzer, the emergent light of analyzer is respectively by the second collimater, the first photodetector, and the 3rd collimater, the second photodetector, the emergent light of the emergent light of the first photodetector and the second photodetector is input to respectively signal processing unit, signal processing unit is to light source output drive signal, described voltage sensor also comprises: modulator electrode and ground electrode, modulator electrode and ground electrode are all placed in responsive optical crystal side, modulator electrode connects signal processing unit, ground electrode connects signal processing unit. the invention also discloses a kind of method of measuring voltage. after the application embodiment of the present invention, can ensure the accuracy of direct current and ac voltage measurement.

Description

A kind of method of measuring voltage and voltage sensor

Technical field

The application relates to photoelectricity test technical field, more specifically, relates to a kind of method and voltage sensor of measuring voltageDevice.

Background technology

Electric power is traction and the basis of social development, and the safety of power system is extremely closed socio-economic development and national securityImportant. Electric current and voltage are two basic parameters of power system, equal in the every field of generating, power transmission and distribution, electricity consumptionNeed to carry out Measurement accuracy to electric current, voltage.

Voltage sensor can be realized the measurement to voltage, for relay protection, electric energy metrical and power network monitoring provide basePlinth data, are the nucleus equipments of electric power network, its reliability, security, long-time stability and power system safe,Stable operation is directly related.

The method of traditional measurement high pressure comprises electromagnetic potential sensor, resitstance voltage divider, capacitive divider and Hall electricityPressure sensors etc. are multiple, and wherein electromagnetic potential sensor and capacitive divided voltage transformer obtain in power systemExtensive use.

But along with the raising of voltage class of electric power system and the increase of capacity, measure and protect improving constantly of requiring,Its weak point becomes increasingly conspicuous, and main manifestations is:

(1), insulation difficulty is large, because insulation makes the out-of-proportion raising of volume, weight and price of transformer.

(2), intrinsic magnetic saturation, the dynamic range of transformer iron core structure is little, frequency band is narrow.

(3), secondary output signal can not be directly and the digitized measurement and protection equipment interface.

(4), capacitive divided voltage transformer easily produces ferromagnetic resonance.

It is " non-that novel optical voltage transformer based on bubble Ke Ersi (Pockels) electrooptic effect has natural photoelectricity isolationInsertion type " measurement advantage, electric insulating quality is good, antijamming capability is strong, fast response time, volume are little, lightweight andThe series of advantages such as safe and reliable, and be convenient to and fiber optic communication, computer system networking, complete monitoring, control formedSystem and protecting network have very wide application prospect in power system, become the technology of voltage sensor developmentDirection.

Existing optical voltage sensor adopts double photo paths technical scheme more, can reduce preferably light source power notThe stable error of bringing. Just can calculate voltage by the caused light phase of tested alternating voltage.

Voltage transformer double light path output intensity is expressed as:

I_o+＝K₁I_i(1+δ)（1）

I_o-＝K₂I_i(1-δ)（2）

Wherein, K₁,K₂Be respectively the gain of two-way light path, I_iFor input light intensity, δ is that tested alternating voltage is causedLight phase. Be zero to be that δ is zero when tested alternating voltage, only have DC component. The light intensity of DC component in two-way light intensityBe respectively:

$I_{o+}^{\mathrm{dc}}=K_1{I}_i---\left(3\right)$

$I_{o-}^{\mathrm{dc}}=K_2{I}_i---\left(4\right)$

Obtained by (1)～(4) formula:

$\mathrm{\δ}=\frac{\frac{I_{o+}}{I_{o+}^{\mathrm{dc}}}-\frac{I_{o-}}{I_{o-}^{\mathrm{dc}}}}{2}---\left(5\right)$

In prior art, have following technical problem, when containing DC component in measured signal, the accuracy of δ is lower, thenCalculate measuring voltage by δ, further cannot ensure the accuracy of measuring voltage.

Summary of the invention

The embodiment of the present invention proposes a kind of method of measuring voltage, can ensure the accuracy of voltage measurement.

The embodiment of the present invention also proposes a kind of voltage sensor, can ensure the accuracy of voltage measurement.

The technical scheme of the embodiment of the present invention is as follows:

A kind of voltage sensor, the emergent light order in light source by first collimator, the polarizer, λ/4 wave plate,Responsive optical crystal and analyzer, the emergent light of analyzer passes through respectively the second collimater, the first photodetector,And the 3rd collimater, the second photodetector, the emergent light of the first photodetector and the second photodetectorEmergent light be input to respectively signal processing unit, signal processing unit is to light source output drive signal, described electricityPressure sensor also comprises: modulator electrode and ground electrode,

Modulator electrode and ground electrode are all placed in responsive optical crystal side, and modulator electrode connects signal processing unit, ground electricityThe utmost point connects signal processing unit.

The voltage of described modulator electrode comprises square-wave frequency modulation voltage.

The frequency of described square-wave frequency modulation voltage is at least 10 times of tested electric voltage frequency.

Described modulator electrode comprises the first modulator electrode and the second modulator electrode, the first modulator electrode and the second modulation electricThe utmost point is positioned at the left and right sides of responsive optical crystal, and ground electrode is positioned at the downside of responsive optical crystal.

Described modulator electrode and described ground electrode are all positioned at the downside of described responsive optical crystal, and described ground electrode is in instituteState the below of modulator electrode.

A method for measuring voltage, described method comprises:

Responsive optical crystal is applied to forward modulation voltage, in the first light path, obtain the first light intensity, in the second light pathIn obtain the 3rd light intensity;

Responsive optical crystal is applied to negative sense modulation voltage, in the first light path, obtain the second light intensity, in the second light pathIn obtain the 4th light intensity;

Calculate according to the first light intensity, the second light intensity, the 3rd light intensity and the 4th light intensity the phase difference that tested electric field is corresponding,And tested voltage.

Described modulation voltage comprises square-wave frequency modulation voltage.

The frequency of described square-wave frequency modulation voltage is at least 10 times of tested electric voltage frequency.

From technique scheme, can find out, in embodiments of the present invention responsive optical crystal be applied to forward modulation electricPress, in the first light path, obtain the first light intensity, in the second light path, obtain the 3rd light intensity; Responsive optical crystal is appliedNegative sense modulation voltage obtains the second light intensity in the first light path, obtains the 4th light intensity in the second light path; According to firstLight intensity, the second light intensity, the 3rd light intensity and the 4th light intensity are calculated the phase difference that tested electric field is corresponding, and measuring voltage.Due to responsive optical crystal is applied to modulation voltage, according to the first light intensity obtaining, the second light intensity, the 3rd light intensity andFour light intensity are being calculated phase difference corresponding to tested electric field, and the direct current signal in its computational process and measured signal is irrelevant, because ofThis can improve the accuracy of light phase, the further accuracy of measuring voltage.

Brief description of the drawings

Fig. 1 is the structural representation of voltage sensor;

Fig. 2 is the method flow schematic diagram of measuring voltage;

Fig. 3 is the sampling time sequence figure of the first detector;

Fig. 4 is the sampling time sequence figure of the second detector;

Fig. 5 is modulator electrode position view in embodiment mono-;

Fig. 6 is modulator electrode position view in embodiment bis-.

Detailed description of the invention

For making the object, technical solutions and advantages of the present invention express clearlyer, below in conjunction with accompanying drawing andThe present invention is further described in more detail for specific embodiment.

In embodiments of the present invention, by responsive optical crystal is applied to modulation voltage, in the process of calculating phasic differenceBe not subject to whether existing the impact of DC current, thereby ensured the accuracy of phasic difference, and then ensured tested electricityThe accuracy of pressing.

The structural representation of voltage sensor referring to accompanying drawing 1, emergent light in light source order by first collimator,The polarizer, λ/4 wave plate, responsive optical crystal and analyzer, the emergent light of analyzer is by the second collimater, firstPhotodetector; The emergent light of analyzer is by the 3rd collimater, the second photodetector.

The output twin shaft of analyzer is respectively through collimater, single-mode fiber and the first photodetector, the second photodetectorBe connected. Be called the first light path via the light path of the first photodetector, be called via the light path of the second photodetectorThe second light path. The first photodetector, the second photodetector carries out, after opto-electronic conversion, being input to signal processing unitThe rear data signal that transfers to respectively, after calculation process, signal processing unit is to the size of light source outputting drive voltage value.

Have modulator electrode and ground electrode at responsive optical crystal side, the voltage between modulator electrode and ground electrode is applied toOn responsive optical crystal, cause phasic difference. Wherein, modulator electrode connects signal processing unit, and ground electrode connects signal placeReason unit.

Participating in accompanying drawing 2 is method flow schematic diagrames of measuring voltage, specifically comprises the following steps:

201, responsive optical crystal is applied to forward modulation voltage, in the first light path, obtain the first light intensity, at the second lightIn road, obtain the 3rd light intensity; Responsive optical crystal is applied to negative sense modulation voltage, in the first light path, obtains the second light intensity,In the second light path, obtain the 4th light intensity.

The light intensity that the first photodetector and the second photodetector detect is respectively:

I_o+＝K₁I_i(1+δ)（6）

I_o-＝K₂I_i(1-δ)（7）

Wherein, K₁,K₂Be respectively the gain of two-way light path, I_iFor input light intensity, δ is for applying the caused light phase of voltagePosition. δ is produced by tested electric field and modulated electric fields stack. In the time that the voltage of modulator electrode is square-wave frequency modulation voltage,

δ＝δ_E±δ_Ud（8）

δ_EFor the phase difference that tested electric field produces, δ_UdFor the phase difference of modulated electric fields generation. Modulation voltage adopts square wave to adjustSystem. Square wave frequency is at least 10 times of tested electric voltage frequency. For example can be taken as 20kHz, square wave generating positive and negative voltage amplitude phaseDeng. Certainly, also can adopt sine wave modulation voltage, cosine wave modulation voltage is modulated. Now δ is by testedElectric field and modulated electric fields stack produce, and the relation of the phase difference that δ and modulated electric fields produce not is shown in (8), butNeed to change accordingly according to modulation voltage, concrete computational process repeats no more.

Under square-wave electric field modulation, shown in the sampling time sequence accompanying drawing 3 of the first photodetector signal of telecommunication, CLK'sIn pulse period, repeatedly sample, sampled data averages processing, can effectively reduce optical noise. Accompanying drawing 3The sample numerical value of positive square wave and losing side ripple is respectively D1, D2, can be expressed as:

$D_1=I_{o+}^1=K_1{I}_i(1+{\mathrm{\δ}}_E+{\mathrm{\δ}}_{\mathrm{Ud}})---\left(9\right)$

$D_2=I_{o+}^2=K_1{I}_i(1+{\mathrm{\δ}}_E-{\mathrm{\δ}}_{\mathrm{Ud}})---\left(10\right)$

Under this square wave Electric Field Modulated, shown in the sampling time sequence accompanying drawing 4 of the second photodetector signal of telecommunication, positive square waveBe respectively D3, D4 with the sample numerical value of losing side ripple, can be expressed as:

$D_3=I_{o-}^1=K_2{I}_i(1-{\mathrm{\δ}}_E-{\mathrm{\δ}}_{\mathrm{Ud}})---\left(11\right)$

$D_4=I_{o-}^2=K_2{I}_i(1-{\mathrm{\δ}}_E+{\mathrm{\δ}}_{\mathrm{Ud}})---\left(12\right)$

202, calculate according to the sampled value (D1～D4) of the first light intensity, the second light intensity, the 3rd light intensity and the 4th light intensityThe phase difference that tested electric field is corresponding, and tested voltage.

Can be obtained by formula (9) (10) (11) (12) so:

$D_1-D_2=I_{o+}^1-I_{o+}^2={2K}_1{I}_i{\mathrm{\δ}}_{\mathrm{Ud}}---\left(13\right)$

$D_1+D_2=I_{o+}^1+I_{o+}^2={2K}_1{I}_i(1+{\mathrm{\δ}}_E)---\left(14\right)$

$D_3-D_4=I_{o-}^1-I_{o-}^2={-2K}_2{I}_i{\mathrm{\δ}}_{\mathrm{Ud}}---\left(15\right)$

$D_3+D_4=I_{o-}^1+I_{o-}^2={2K}_2{I}_i(1-{\mathrm{\δ}}_E)---\left(16\right)$

Can be obtained by formula (13) (14) (15) (16):

(D₁-D₂)(D₃+D₄)＝4K₁K₂I_i ²δ_Ud(1-δ_E)＝K(1-δ_E)（17）

(D₁+D₂)(D₃-D₄)＝-4K₁K₂I_i ²δ_Ud(1+δ_E)＝-K(1+δ_E)（18）

So calculate δ_EFor

${\mathrm{\δ}}_E=\frac{(D_1+D_2)(D_3-D_4)+(D_1-D_2)(D_3+D_4)}{(D_1+D_2)(D_3-D_4)-(D_1-D_2)(D_3+D_4)}=\frac{D_1{D}_3-D_2{D}_4}{D_2{D}_3-D_1{D}_4}---\left(19\right)$

From (19) formula, with respect to modulating frequency (more than being generally 20kHz), tested electric field signal (is handed overStream, direct current or higher hamonic wave signal) be low frequency signal, by high frequency modulated demodulation of the present invention, realize δ_E'sResult of calculation and its composition are irrelevant, when therefore can realizing alternating current-direct current, measure, and have ensured the accurate of voltage measurementProperty.

In addition, applying of modulator electrode can vertical tested electric field or parallel tested electric field, the final electricity of realizing of two schemesField modulation effect is consistent.

On modulator electrode, apply the voltage perpendicular to tested electric field referring to accompanying drawing 5 for embodiment mono-, modulator electrode bagDraw together the first modulator electrode and the second modulator electrode, the first modulator electrode and the second modulator electrode are arranged at respectively responsive opticsThe both sides of crystal, ground electrode is positioned at the downside of responsive optical crystal. The first modulator electrode, the second modulator electrode and ground electricityThe utmost point is connected with signal processing unit respectively.

On modulator electrode, apply for embodiment bis-voltage that is parallel to tested electric field referring to accompanying drawing 6, modulator electrode positionIn the downside of responsive optical crystal, ground electrode is positioned at the downside of modulator electrode, passes through thin between modulator electrode and ground electrodeInsulation board separates. Modulator electrode is connected with signal processing unit respectively with ground electrode.

The above, be only preferred embodiment of the present invention, is not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any amendment of doing, be equal to replacement, improvement etc., all should compriseWithin protection scope of the present invention.

Claims (1)

1. a method for measuring voltage, is characterized in that, for voltage sensor,

Emergent light order in light source is by first collimator, the polarizer, λ/4 wave plate, quick of described voltage sensorSensitometry crystal and analyzer, the emergent light of analyzer divides two-way, and a road is successively by the second collimater, the first photoelectricityDetector, and another road is successively by the 3rd collimater, the second photodetector, the outgoing of the first photodetectorThe emergent light of light and the second photodetector is input to respectively signal processing unit, and signal processing unit drives to light source outputMoving signal,

Described voltage sensor also comprises: modulator electrode and ground electrode, described modulator electrode and described ground electrode are all placed inResponsive optical crystal side, described modulator electrode connects signal processing unit, and described ground electrode connects signal processing unit;

Described method comprises:

Described responsive optical crystal is applied to forward modulation voltage, in the first light path, obtain the first light intensity, at the second lightIn road, obtain the 3rd light intensity;

Described responsive optical crystal is applied to negative sense modulation voltage, in the first light path, obtain the second light intensity, at the second lightIn road, obtain the 4th light intensity;

Calculate according to the first light intensity, the second light intensity, the 3rd light intensity and the 4th light intensity the tested electric field pair that tested voltage producesPhase difference between described the first light path and second light path of answering, and tested voltage;

Described modulation voltage comprises square-wave frequency modulation voltage;

The frequency of described square-wave frequency modulation voltage is at least 10 times of tested electric voltage frequency;

The first light intensity D₁＝K₁I_i(1+δ_E+δ_Ud)；

The second light intensity D₂＝K₁I_i(1+δ_E-δ_Ud)；

The 3rd light intensity D₃＝K₂I_i(1-δ_E-δ_Ud)；

The 4th light intensity D₄＝K₂I_i(1-δ_E+δ_Ud)；

K₁,K₂Be respectively the gain of two-way light path, I_iFor input light intensity, δ_EFor the phase difference that tested electric field produces, δ_UdFor the phase difference of modulated electric fields generation;

${\mathrm{\δ}}_E=\frac{(D_1+D_2)(D_3-D_4)+(D_1-D_2)(D_3+D_4)}{(D_1+D_2)(D_3-D_4)+(D_1-D_2)(D_3+D_4)}=\frac{D_1{D}_3-D_2{D}_4}{D_2{D}_3-D_1{D}_4}.$